2 * ++Copyright++ 1985, 1989, 1993
4 * Copyright (c) 1985, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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35 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
37 * Permission to use, copy, modify, and distribute this software for any
38 * purpose with or without fee is hereby granted, provided that the above
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40 * the name of Digital Equipment Corporation not be used in advertising or
41 * publicity pertaining to distribution of the document or software without
42 * specific, written prior permission.
44 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
46 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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56 #if defined(LIBC_SCCS) && !defined(lint)
57 static char sccsid[] = "@(#)res_init.c 8.1 (Berkeley) 6/7/93";
58 static char rcsid[] = "$Id$";
59 #endif /* LIBC_SCCS and not lint */
61 #include <sys/param.h>
62 #include <sys/socket.h>
63 #include <netinet/in.h>
64 #include <arpa/inet.h>
65 #include <arpa/nameser.h>
70 #if defined(BSD) && (BSD >= 199103)
75 # include "../conf/portability.h"
78 #if defined(USE_OPTIONS_H)
79 # include "../conf/options.h"
82 static void res_setoptions __P((char *, char *));
85 static u_int32_t net_mask __P((struct in_addr));
88 #if !defined(isascii) /* XXX - could be a function */
89 # define isascii(c) (!(c & 0200))
93 * Resolver state default settings.
96 struct __res_state _res;
99 * Set up default settings. If the configuration file exist, the values
100 * there will have precedence. Otherwise, the server address is set to
101 * INADDR_ANY and the default domain name comes from the gethostname().
103 * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
104 * rather than INADDR_ANY ("0.0.0.0") as the default name server address
105 * since it was noted that INADDR_ANY actually meant ``the first interface
106 * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
107 * it had to be "up" in order for you to reach your own name server. It
108 * was later decided that since the recommended practice is to always
109 * install local static routes through 127.0.0.1 for all your network
110 * interfaces, that we could solve this problem without a code change.
112 * The configuration file should always be used, since it is the only way
113 * to specify a default domain. If you are running a server on your local
114 * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
115 * in the configuration file.
117 * Return 0 if completes successfully, -1 on error
122 register char *cp, **pp;
123 register int n, dots;
125 int nserv = 0; /* number of nameserver records read from file */
134 * These four fields used to be statically initialized. This made
135 * it hard to use this code in a shared library. It is necessary,
136 * now that we're doing dynamic initialization here, that we preserve
137 * the old semantics: if an application modifies one of these three
138 * fields of _res before res_init() is called, res_init() will not
139 * alter them. Of course, if an application is setting them to
140 * _zero_ before calling res_init(), hoping to override what used
141 * to be the static default, we can't detect it and unexpected results
142 * will follow. Zero for any of these fields would make no sense,
143 * so one can safely assume that the applications were already getting
144 * unexpected results.
147 _res.retrans = RES_TIMEOUT;
151 _res.options = RES_DEFAULT;
154 _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
156 _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
158 _res.nsaddr.sin_family = AF_INET;
159 _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
164 /* Allow user to override the local domain definition */
165 if ((cp = getenv("LOCALDOMAIN")) != NULL) {
166 (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
170 * Set search list to be blank-separated strings
171 * from rest of env value. Permits users of LOCALDOMAIN
172 * to still have a search list, and anyone to set the
173 * one that they want to use as an individual (even more
174 * important now that the rfc1535 stuff restricts searches)
179 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
180 if (*cp == '\n') /* silly backwards compat */
182 else if (*cp == ' ' || *cp == '\t') {
191 /* null terminate last domain if there are excess */
192 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
198 if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
199 /* read the config file */
200 while (fgets(buf, sizeof(buf), fp) != NULL) {
202 if ((*buf == ';') || (*buf == '#'))
204 /* read default domain name */
205 if (!strncmp(buf, "domain", sizeof("domain") - 1)) {
206 if (haveenv) /* skip if have from environ */
208 cp = buf + sizeof("domain") - 1;
209 while (*cp == ' ' || *cp == '\t')
211 if ((*cp == '\0') || (*cp == '\n'))
213 (void)strncpy(_res.defdname, cp,
214 sizeof(_res.defdname) - 1);
215 if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
220 /* set search list */
221 if (!strncmp(buf, "search", sizeof("search") - 1)) {
222 if (haveenv) /* skip if have from environ */
224 cp = buf + sizeof("search") - 1;
225 while (*cp == ' ' || *cp == '\t')
227 if ((*cp == '\0') || (*cp == '\n'))
229 (void)strncpy(_res.defdname, cp,
230 sizeof(_res.defdname) - 1);
231 if ((cp = strchr(_res.defdname, '\n')) != NULL)
234 * Set search list to be blank-separated strings
241 *cp && pp < _res.dnsrch + MAXDNSRCH;
243 if (*cp == ' ' || *cp == '\t') {
251 /* null terminate last domain if there are excess */
252 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
259 /* read nameservers to query */
260 if (!strncmp(buf, "nameserver", sizeof("nameserver") - 1) &&
264 cp = buf + sizeof("nameserver") - 1;
265 while (*cp == ' ' || *cp == '\t')
267 if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
268 _res.nsaddr_list[nserv].sin_addr = a;
269 _res.nsaddr_list[nserv].sin_family = AF_INET;
270 _res.nsaddr_list[nserv].sin_port =
271 htons(NAMESERVER_PORT);
277 if (!strncmp(buf, "sortlist", sizeof("sortlist") -1)) {
280 cp = buf + sizeof("sortlist") - 1;
281 while (nsort < MAXRESOLVSORT) {
282 while (*cp == ' ' || *cp == '\t')
284 if (*cp == '\0' || *cp == '\n' || *cp == ';')
287 while (*cp && *cp != '/' &&
288 isascii(*cp) && !isspace(*cp))
292 if (inet_aton(net, &a)) {
293 _res.sort_list[nsort].addr = a;
297 while (*cp && isascii(*cp) && !isspace(*cp))
301 if (inet_aton(net, &a)) {
302 _res.sort_list[nsort].mask = a.s_addr;
304 _res.sort_list[nsort].mask =
305 net_mask(_res.sort_list[nsort].addr);
308 _res.sort_list[nsort].mask =
309 net_mask(_res.sort_list[nsort].addr);
318 if (!strncmp(buf, "options", sizeof("options") -1)) {
319 res_setoptions(buf + sizeof("options") - 1, "conf");
324 _res.nscount = nserv;
330 if (_res.defdname[0] == 0) {
331 if (gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
332 (cp = strchr(buf, '.'))) {
333 (void)strcpy(_res.defdname, cp + 1);
337 /* find components of local domain that might be searched */
338 if (havesearch == 0) {
340 *pp++ = _res.defdname;
345 for (cp = _res.defdname; *cp; cp++)
346 dots += (*cp == '.');
349 while (pp < _res.dnsrch + MAXDFLSRCH) {
350 if (dots < LOCALDOMAINPARTS) {
353 cp = strchr(cp, '.') + 1; /* we know there is one */
359 if (_res.options & RES_DEBUG) {
360 printf(";; res_init()... default dnsrch list:\n");
361 for (pp = _res.dnsrch; *pp; pp++) {
362 printf(";;\t%s\n", *pp);
364 printf(";;\t..END..\n");
370 if ((cp = getenv("RES_OPTIONS")) != NULL) {
371 res_setoptions(cp, "env");
373 _res.options |= RES_INIT;
379 res_setoptions(options, source)
380 char *options, *source;
386 if (_res.options & RES_DEBUG) {
387 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
392 /* skip leading and inner runs of spaces */
393 while (*cp == ' ' || *cp == '\t')
395 /* search for and process individual options */
396 if (!strncmp(cp, "ndots:", sizeof("ndots:")-1)) {
397 i = atoi(cp + sizeof("ndots:") - 1);
398 if (i <= RES_MAXNDOTS)
401 _res.ndots = RES_MAXNDOTS;
403 if (_res.options & RES_DEBUG) {
404 printf(";;\tndots=%d\n", _res.ndots);
407 } else if (!strncmp(cp, "debug", sizeof("debug")-1)) {
409 if (!(_res.options & RES_DEBUG)) {
410 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
412 _res.options |= RES_DEBUG;
414 printf(";;\tdebug\n");
417 /* XXX - print a warning here? */
419 /* skip to next run of spaces */
420 while (*cp && *cp != ' ' && *cp != '\t')
427 net_mask(in) /* XXX - should really use system's version of this */
430 register u_int32_t i = ntohl(in.s_addr);
433 return (htonl(IN_CLASSA_NET));
434 else if (IN_CLASSB(i))
435 return (htonl(IN_CLASSB_NET));
437 return (htonl(IN_CLASSC_NET));